Tire Pressure Low Warning Came On Yesterday

[GrySql]

That doesn't make sense. I run my tires over spec, changed psi up to 10 higher than the door sticker, even changed tire brands without resetting the sensors and use different pressures until I feel it's the right setup for the car.

I have never had a TPMS warning.

[murphy]

The TPMS sensors send the actual tire pressure to the computer. I've read them all with my OBD II scanner. It's up to the computer to decide if they are too low. It's likely that something caused the signal from one of the sensors to not be received.

[corncobs]

That doesn't make sense. I run my tires over spec, changed psi up to 10 higher than the door sticker, even changed tire brands without resetting the sensors and use different pressures until I feel it's the right setup for the car.

I have never had a TPMS warning.

Are you sure your FFH has them? ;)

[SteveB_TX]

Are you sure your FFH has them? ;)

 

I believe TMPS became mandatory in for all vehicles 10klbs or less effective with the 2007 model year. As usual, don't quote me on that! :)

 

Edit: Wait. What? Oh I see... the smirk face. haha. Never mind then. :)

Edited January 17, 2015 by SteveB_TX

[murphy]

September 1, 2007 was the mandatory date, by an act of Congress, for all vehicles under 10,000 lbs to have TPMS sensors.

[Barsoom]

The TPMS sensors send the actual tire pressure to the computer. I've read them all with my OBD II scanner. It's up to the computer to decide if they are too low. It's likely that something caused the signal from one of the sensors to not be received.

It's possible that something happened when I drove through a back alley with high water on a cool rainy day. Maybe the sudden cooling from the water caused a brief sensor glitch? If so, I'm surprised that it didn't reset itself later with driving

 

I have a cheap Chinese OBD2 reader, but I didn't think to use it to read the the sensors.

 

I'll have to see if this ever happens again.

[acdii]

It does look at pressure differential. I run at 40 PSI, and I had a slow leaker, when it got down to 34 PSI, which is the recommended PSI, the TPMS would come on. Thats a 6 PSI imbalance. It took 3 key cycles for it to clear when the tires were at the same pressure.

[FordService]

I took my car in today. They said the pressure was a little higher than spec, and slightly imbalanced across the tires. They said the sensor was okay. It's odd that high pressure triggers a low pressure warning, but nothing surprises me anymore.

My offer to look into this still stands. :)

 

Meagan

[lolder]

The government requirement for TPMSs is that they alert when any tire is 25% below the drivers door sill sticker value. I'd be surprised if they alarmed for differences or a higher value. The intent is to protect against under inflation

[Barsoom]

The warning came on again yesterday as I was driving into my garage at the end of the day.

 

I must either have a slow leak in the valve stem or rim, because there are no nails in the tire. Or it's a bad sensor or a defective wheel that's slowly letting air out?

 

Back to Ford. This was a good run. No issues since January!

[lolder]

What does the pressure read in all the tires with a tire pressure gauge? Sounds like a sensor battery may be dying.

[corncobs]

That's what the warning is for isn't it?

 

I had the same after putting my summer tires back on. Somehow by laying around one tire lost some air no big deal in my opinion.

Put some fresh air back in and the warning will go away no need for a dealer visit but that's just me thinking out loud. ;)

Edited May 5, 2015 by corncobs

[Barsoom]

I will check it tonight when I get home. My afternoon drive is only about 6 miles, enough to warm up the tires.

[GrySql]

TPMS Warning Indicator

The IPC receives the tire pressure warning indicator request from the GWM over the High Speed Controller Area Network 3 (HS3-CAN). The GWM receives the tire pressure warning indicator request from the BCM over the High Speed Controller Area Network 1 (HS1-CAN).

If the BCM determines the tire pressure has exceeded the low tire pressure limits, the tire pressure warning indicator request message is sent to the IPC to illuminate the TPMS warning indicator.

If a TPMS monitor or sensor fault condition exists, the BCM sends the tire pressure warning indicator request message to the IPC to flash the TPMS warning indicator. The IPC flashes the TPMS warning indicator for 75 seconds then turns the indicator on solid.

[Cobra348]

 

That most likely means you have a sensor that has somehow fallen out of calibration. If the system was not detecting 4 valid signals, it would say "TIRE PRESSURE SENSOR FAULT" or "TIRE PRESSURE MONITOR FAULT".

Perhaps Fusion is different, but I had a sensor go bad on a Fiesta and it delivered the "Tire Pressure Monitor Fault" message. Only by using the triggering tool on each corner was the bad sensor located - it failed to respond. Replaced the sensor, retrain cycle and all was good with the world.

 

I also learned that the "Tire Pressure Low" usually would go off if the pressure was more than 10% lower than that recommended on the door jamb stickers from Ford. On 15" Fiesta it would trigger about 28-30 PSI on a recommended pressure of 32 PSI. Fusion 17" rims are 35 on the sticker so I think the low warning would trigger somewhere in the 30-32 PSI range. OP stated pressures were all above the PSI recommendations, so I doubt a tire is low.

 

I vote borked sensor ...

[billford]

If you have a Scangauge, you can program it to monitor the tire pressures from the drivers seat.

[Waldo]

Perhaps Fusion is different, but I had a sensor go bad on a Fiesta and it delivered the "Tire Pressure Monitor Fault" message. Only by using the triggering tool on each corner was the bad sensor located - it failed to respond. Replaced the sensor, retrain cycle and all was good with the world.

 

I also learned that the "Tire Pressure Low" usually would go off if the pressure was more than 10% lower than that recommended on the door jamb stickers from Ford. On 15" Fiesta it would trigger about 28-30 PSI on a recommended pressure of 32 PSI. Fusion 17" rims are 35 on the sticker so I think the low warning would trigger somewhere in the 30-32 PSI range. OP stated pressures were all above the PSI recommendations, so I doubt a tire is low.

 

I vote borked sensor ...

 

If you were seeing the light on your Fiesta at 28-30psi then you must have a bad pressure gauge. As noted earlier in the thread, they are set to 25% below the door sticker, this is a Federal Requirement. That should be 24psi on a 32psi nominal, so I suspect if you were seeing the light on when your gauge read 28, then you bumped them up to where your gauge said 32, you were actually only setting them to 28.

[Barsoom]

I have a cheap Chinese OBDII reader. If I drive with it connected, it eventually throws a fault message and I have to shut off the on to clear it. Still, I'll try it in my garage to see what it can read with Torque Pro.

 

Maybe it's time to buy a real reader? :)

[FordService]

The warning came on again yesterday as I was driving into my garage at the end of the day.

 

I must either have a slow leak in the valve stem or rim, because there are no nails in the tire. Or it's a bad sensor or a defective wheel that's slowly letting air out?

 

Back to Ford. This was a good run. No issues since January!

I'll be happy to look into this, Barsoom. I'll need your VIN, mileage, best daytime phone number, full name, and dealer name/location. :)

 

Meagan

[Barsoom]

Well I'll be...

 

I'm at Ford Service right now and they found a small corner piece of a razor blade in one of the tires that was probably causing a slow leak. I don't know how long that's been in there. I guess the sensor worked as designed, this time.

 

They are fixing the tire now.

Edited May 8, 2015 by Barsoom

[hybridbear]

I have a cheap Chinese OBDII reader. If I drive with it connected, it eventually throws a fault message and I have to shut off the on to clear it. Still, I'll try it in my garage to see what it can read with Torque Pro.

 

Maybe it's time to buy a real reader? :)

You can download FORScan for Android right now for free and use that to see your individual tire pressures. They also have a free version for Windows and a paid version for iOS. FORScan will allow you to see if a sensor is bad versus low tire pressure.

 

Well I'll be...

 

I'm at Ford Service right now and they found a small corner piece of a razor blade in one of the tires that was probably causing a slow leak. I don't know how long that's been in there. I guess the sensor worked as designed, this time.

 

They are fixing the tire now.

I hope they aren't charging you... We recently got a screw in the tire of the Focus Electric and took it to Discount Tire who fixed it for free.

[Texasota]

I hope they aren't charging you... We recently got a screw in the tire of the Focus Electric and took it to Discount Tire who fixed it for free.

 

Some (maybe many) tire dealers will fix tire damage (resulting from road hazards) at no charge when the tire was originally purchased from them and that is a great customer service. But, assuming Barsoom's tires are OEM (not purchased at the Ford service deparment) why should it be expected that the dealership fix them at no charge? That does not seam reasonable to me but only my opinion and others may differ.

Edited May 10, 2015 by Texasota

[hybridbear]

 

Some (maybe many) tire dealers will fix tire damage (resulting from road hazards) at no charge when the tire was originally purchased from them and that is a great customer service. But, assuming Barsoom's tires are OEM (not purchased at the Ford service deparment) why should it be expected that the dealership fix them at no charge? That does not seam reasonable to me but only my opinion and others may differ.

As far as I know Discount Tire will always fix tires for free. The Focus tires are OEM and they rotate the tires & fix them for free. That's why we go to Discount Tire. Edited May 10, 2015 by hybridbear

[Waldo]

Yep, I've had Discount tire fix many tires for free, most of which were not bought from them.

 

I'm guessing that their business model is they figure say 20-30% of all tires brought it for the free fix will be non-repairable, so since you're already there, you will buy the replacement from them.

Edited May 11, 2015 by Waldo

[hybridbear]

Yep, I've had Discount tire fix many tires for free, most of which were not bought from them.

 

I'm guessing that their business model is they figure say 20-30% of all tires brought it for the free fix will be non-repairable, so since you're already there, you will buy the replacement from them.

You're probably right... Discount Tire will also price match tires from other shops or online which has saved us money in the past when buying new tires.